Emulating multi-channel scattering based on the eigenvector continuation in the discrete basis formalism

We construct an emulator for a multi-channel scattering problem based on the eigenvector continuation. To this end, we employ the Kohn variational principle formulated in the discrete basis formalism. We apply this to one-dimensional scattering problems with a Gaussian barrier. Both for a single-channel and two-channel problems, we demonstrate that the penetration probability as well as the wave functions are well reproduced by the emulator. In particular, the energy dependence of the penetrability in a wider range of energy from well below the barrier to well above the barrier is successfully reproduced.